“We have not received the truth. Congress should hold a hearing and call as witnesses those who ordered the arrest and demand they explain and justify it,” he wrote.

“It is unlikely that a plausible and credible explanation will be offered, but Mueller and his FBI agents should at least have an opportunity to set the record straight. Maybe there is a good reason for why the arrest was necessary, but if so, we have not heard it and it is unlikely that the reason involves national security or other secrets,” he said.

“These hearings should lead to legislation setting enforceable standards for when the kind of arrest to which Stone was subjected should be permissible. The power to arrest, using armed FBI agents, handcuffs and shackles must not become a tactic to be used by law enforcement for impermissible reasons. Nor should it become routine. Congress must act to prevent these abuses from recurring.”

Dershowitz said the FBI’s stated reasons for the arrest are “utterly unconvincing.”

“He was not a flight risk, as evidenced by the low bail and easy conditions of release set by the judge without objection from the government. Stone knew he was going to be indicted and if he wanted to flee, he had plenty of time to do so. The same is true of destroying evidence, wiping his electronics or doing anything else that would warrant an arrest rather than a notice to his lawyer to appear in court at a specified time.”

Dershowitz asserted that the “illegitimate purpose of the arrest was to intimidate the potential witness – namely Stone – into not invoking his constitutional right to remain silent, rather than to testify as a government witness. ”

“The arrest was nothing more than a show of toughness – a foretaste of what Stone could expect if he did not cooperate with Mueller,” he said.

He said police do it all the time, but enough with that.

“As Judge T.S. Ellis, III, who presided over the Manafort trial, observed: ‘You don’t really care about Mr. Manafort’s bank fraud – what you really care about is what information Mr. Manafort could give you that would reflect on Mr. Trump or lead to his prosecution or impeachment,'” he wrote.

The danger is that defendants not only could “sing,” or testify, they could “compose,” meaning make up evidence.

“If Hillary Clinton had been elected president and if a special prosecutor had arrested one of her associates in the rough and demeaning manner by which Stone was arrested, civil libertarians would be up in arms,” he said. “But because the arrest is of a Trump associate and the purpose is to get evidence against President Trump, we have not heard from fair-weather civil libertarians who use civil liberties and constitutional rights as tactics to serve their partisan political agendas.”